\usepackage{ifpdf}
\ifpdf
\usepackage[pdftex]{graphicx}
\else
\usepackage[dvips]{graphicx}
\fi

\newcommand{\laig}[2]{\ifpdf
\includegraphics[#2]{fruit/#1.pdf}
\else
\includegraphics[#2]{fruit/#1.eps}
\fi}

\newcommand{\lemon}{\laig{lemon}{height=\baselineskip}}
\newcommand{\melon}{\laig{melon}{height=\baselineskip}}
\newcommand{\watermelon}{\laig{watermelon}{height=\baselineskip}}
\newcommand{\tomato}{\laig{tomato}{height=\baselineskip}}
\newcommand{\fdiamond}{\laig{diamond}{height=0.8\baselineskip}}
\newcommand{\apple}{\laig{apple}{height=\baselineskip}}
\newcommand{\banana}{\laig{banana}{height=\baselineskip}}
\newcommand{\pbanana}{\laig{pbanana}{height=\baselineskip}}
\newcommand{\juice}{\laig{juice}{height=\baselineskip}}

\newcommand{\fth}[1]{#1_{\textbf{th}}}
% \newcommand{\lemon}{\ifpdf
% \includegraphics{fruit/lemon.pdf}
% \else
% \includegraphics{fruit/lemon.eps}
% \fi}
% \newcommand{\melon}{\ifpdf
% \includegraphics{fruit/melon.pdf}
% \else
% \includegraphics{fruit/melon.eps}
% \fi}